Automatic control for the letoff mechanism of looms



1944- Y. H. KURKJIAN 5 AUTOMATIC CONTROL FOR THE LET-OFF MECHANISM OF LOOMS Original Filed March 2 1943 Patented Aug. 15, 1944 AUTOMATIC CONTROL FOR THE LETOFF MECHANISM OF LOOMS Yervant H. Kurkjian, Clifton, N. J.

Original application Mar ch 2, 1943, Serial No.

477,743. Divided and this application September 28, 1943, Serial No. 504,181

4 Claims.

This invention relates to an automatic control for the let-ofi mechanism of looms, and the like, and has for one of its objects the production of a simple and eflicient arrangement of levers for controlling the tension of the brake band of. the warp beam of a loom to automatically maintain a substantially uniform tension upon the warp threads carried by the warp beam.

A further object of this invention is the production of an automatic let-ofi control including a special leverage arrangement which economizes space and at the same time maintains a substantially uniform tension upon the warp threads carried by the warp beam of a loom.

Other objects and advantages of this invention will appear throughout the following specification and claims.

This application constitutes a divisional application from my application relating to an automatic let-off control, filed March 2, 1943, Serial Number 477,743,

In the drawing:

Figure l is a side elevational view of the automatic let-off control, certain parts being broken away;

Figure 2 is a fragmentary front elevational view;

Figure 3 is a fragmentary vertical sectional view taken on line 3-3 of Figure 1.

By referring to the drawing, it will be seen that I!) designates the frame of the loom of a conventional type, which carries the warp beam l I also of the conventional type. Since the present invention relates to the automatic let-01f control mechanism and not to the general loom construction, no effort is made to illustrate the detail construction of the loom itself, and only those parts vital to the invention are illustrated and described.

A tension control arm I2 is pivoted at its lower end l3 to the frame I6, as shown in Figures 1 and 2. This arm l2 carries a warp contact roller l4 at its upper end for direct contact with the warp threads which are wound upon the warp beam II, or the threads upon a spool, as the case may be. A leverage control link [5 is pivotally connected, as at IE, to the arm l2, by means of a journal extending through the slot ll formed in the frame ID. This link carries a pair of transverse rollers 18 and l8 arranged one above the other at the outer end of the link l5, as shown in Figure 1. A tension spring 19 is connected at one end 26 to the frame Ill, and at the other end 2| to the outer roller-carrying end of the link l5-see Figure 1,

A conventional flexible brake band 22 passes around the conventional brake driun 23 and is anchored at one end to the frame In, as at 24. The brake band 22 is connected at its opposite end to the outer end 25 of the brake lever 26. The brake lever 26 is pivoted to the frame ID by means of a pivot 21. The inner end 28 of the brake lever 26 overlies and contacts the upper roller N3 of the link l5.

An intermediate lever 29 is pivoted, as at 30, to the frame l0, and the outer end 3| contacts the under face of the lower roller I8 of the link l5. The downwardly offset inner end 32 of the intermediate lever 29 fits under a transverse pin 33 carried by the weight lever 34. This weight lever 34 is pivoted to the frame ID, as at 35. The lever 34 underlies the lever 29 and carrie an adjustable weight 36 at its outer free end. The weight 36 may be adjusted as to weight by adding additional weight plates and may be adjusted as to position by movement relative to the adjusting notches 31 formed upon the weight lever 34.

By considering Figure 1, it will be seen that as the lever l2 swings toward the center of the beam II, and as the warp is unwound, the position of the rollers l8 and l8 will be shifted upon the levers 26 and 29, the roller l8 moving toward the pivot 21 and the roller 18* moving away from the pivot 30. The intermediate lever 29 is provided with a rocking contact with the pin 33 of the weight lever 34. As the leverage is shifted by the changing position of the rollers l8 and l8 relative to the levers 26 and 29, as a result of the movement of the arm l2, the tension of the brake band 22 will be decreased in proportion to the weight of the weight 36 and the shifting leverage caused by the shifting of position of the rollers l8 and l8 relative to the levers 26 and 29. Consequently, as the warp is unwound from the beam H, the brake band 22 will be loosened due to the shifting leverage and in this manner the warp will at all times be kept substantially at a uniform tension. The tension of the brake band 22 will be regulated in ratio to the unwinding of the warp, the position of the tension con-' trol arm 12, and the leverage differential between the levers 26 and 29 occasioned by the shifting of the rollers l8 and Mia carried by the link 15. In this form of the invention, the weight 36 remains in a selected position and the pull of the weight 36 upon the brake band 22 is adjusted by the shifting leverage interposed between the weight 36 and the brake band 22. The decreased leverage is provided as the size of the warp reduces and permits the arm l2 to swing toward the beam ll, thereby moving the roller-carrying end of the link I5 toward the pivot 21 and away from the pivot 30. In the form shown in Figure 1, it should be noted that the compound leverage arrangement is located directly below the warp and is confined within the area of the frame Ill. The weight lever34 is pivoted near the front of the frame I6 and the free end of this weight lever 34 extends back under the intermediate lever 29 thereby avoiding any protruding parts beyond the front of the frame M.

It should be understood that certain detail changes in the structure illustrated may be employed Without departing from the spirit of the invention, and it should be borne in mind that the-important features of the present invention is the means for automatically controlling the tension of the brake band in ratio to the amount of warp which is unwound from the supporting beam thereby keeping the warp at a constant or substantially uniform tension.

Having described the invention, what I claim is:

1. An automatic let-off control of the class described comprising a let-off mechanism, a beam forming part of said mechanism, a warp wound upon the beam, a brake drum carried by the beam, a brake band passing over the drum, a brake lever mounted adjacent the drum, the brake band engaging one end of the brake lever, a pivot supporting the brake lever, a swinging warp-engaging arm, a link connected to said arm, aligned rollers carried by one end of said link, a pivoted intermediate lever, one of said rollers engaging said brake lever and the other roller engaging one end of said intermediate lever, a pivoted lever engaging the opposite end of said intermediate lever, and an adjustable tension means carried by the outer end of said lever.

2. An automatic let-off control of the class described comprising a let-off mechanism, a beamforming part of said mechanism, a warp wound upon the beam, a. brake drum carried by the beam, a brake band passing over the drum, a brake lever mounted adjacent the drum, the brake band engaging one end of the brake lever,

a pivot supporting the brake lever, a swinging Warp-engaging arm, a link connected to said arm, aligned rollers carried by one end of said link, a pivoted intermediate lever, one of said rollers engaging said brake lever and the other roller engaging one end of said intermediate lever, a pivoted lever engaging the opposite end of said intermediate lever, an adjustable tension means carried by the outer end of said lever, and said lever extending under and being substantially parallel to said intermediate lever.

3. An automatic let-off control of the class described comprising a let-off mechanism, a beam forming part of said mechanism, a warp wound upon the beam, a brake drum carried by the beam, a brake band passing over the drum, a brake lever mounted adjacent the drum, the brake band engaging one end of the brake lever, a pivot supporting the brake lever, a swinging warp-engaging arm, a link connected to said arm, aligned rollers carried by one end of said link, a pivoted intermediate lever, one of said rollers engaging said brake lever and the other roller engaging one end of said intermediate lever, a pivoted weight lever engaging the opposite end of said intermediate lever, and an ad 7 justable weight carried by the outer end of said weight lever.

4. An automatic let-off control of the class described comprising a let-01f mechanism, a beam forming part of said mechanism, a warp wound upon the beam, a brake drum carried by the beam, a brake band passing over the drum, a brake lever mounted adjacent the drum, the brake band engaging one end of the brake lever, a pivot supporting the brake lever, a swinging warp-engaging arm, a link connected to said arm, aligned rollers carried by one end of said link, a pivoted intermediate lever, one of said rollers engaging said brake lever and the other roller engaging one end of said intermediate lever, a pivoted weight lever engaging the opposite end of said intermediate lever, an adjustable weight carried by the outer end of said weight lever, and said weight lever extending under and being'substantially parallel to said intermediate lever.

YERVANT H. KURKJIAN. 

